U.S. patent number 10,006,320 [Application Number 15/123,943] was granted by the patent office on 2018-06-26 for system for controlling valve opening/closing timing.
This patent grant is currently assigned to AISIN SEIKI KABUSHIKI KAISHA. The grantee listed for this patent is AISIN SEIKI KABUSHIKI KAISHA. Invention is credited to Hiroyuki Amano, Takashi Iwaya, Koji Nunami.
United States Patent |
10,006,320 |
Amano , et al. |
June 26, 2018 |
System for controlling valve opening/closing timing
Abstract
A system for controlling valve opening/closing timing that
allows an unlocking operation to be reliably performed is
configured. When extracting a lock member from a recess, a second
control valve is set to an unlock position, a first control valve
is set to a predetermined position, and a relative rotation phase
is displaced. As a result, the relative rotation phase is displaced
in a direction opposite to the direction of displacement by cam
average torque from a camshaft. Afterward, by setting the first
control valve to a neutral position, the relative rotation phase is
displaced by the cam average torque, and when this displacement
occurs, a state in which the lock member is separated from an inner
wall of the recess is created, thus facilitating extraction of the
lock member from the recess.
Inventors: |
Amano; Hiroyuki (Kariya,
JP), Nunami; Koji (Obu, JP), Iwaya;
Takashi (Obu, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
AISIN SEIKI KABUSHIKI KAISHA |
Kariya-shi, Aichi |
N/A |
JP |
|
|
Assignee: |
AISIN SEIKI KABUSHIKI KAISHA
(Kariya-Shi, Aichi, JP)
|
Family
ID: |
54144449 |
Appl.
No.: |
15/123,943 |
Filed: |
March 5, 2015 |
PCT
Filed: |
March 05, 2015 |
PCT No.: |
PCT/JP2015/056470 |
371(c)(1),(2),(4) Date: |
September 06, 2016 |
PCT
Pub. No.: |
WO2015/141475 |
PCT
Pub. Date: |
September 24, 2015 |
Prior Publication Data
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|
|
|
Document
Identifier |
Publication Date |
|
US 20170016359 A1 |
Jan 19, 2017 |
|
Foreign Application Priority Data
|
|
|
|
|
Mar 19, 2014 [JP] |
|
|
2014-056152 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F02D
13/0219 (20130101); F01L 1/3442 (20130101); F01L
1/047 (20130101); F01L 2800/12 (20130101); F01L
2800/16 (20130101); F01L 2001/3443 (20130101); F01L
2001/34426 (20130101); F01L 2001/34483 (20130101); F01L
2001/34453 (20130101); F01L 2001/34466 (20130101); F01L
2001/34473 (20130101); F01L 2001/34463 (20130101); F01L
2820/041 (20130101); F01L 2001/34459 (20130101) |
Current International
Class: |
F01L
1/344 (20060101); F01L 1/047 (20060101); F02D
13/02 (20060101) |
Field of
Search: |
;123/90.17,90.19 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
|
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2010-138699 |
|
Jun 2010 |
|
JP |
|
2011-12576 |
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Jan 2011 |
|
JP |
|
2011-38446 |
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Feb 2011 |
|
JP |
|
2012-219767 |
|
Nov 2012 |
|
JP |
|
WO 2013/187284 |
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Dec 2013 |
|
WO |
|
Other References
International Search Report (PCT/ISA/210) dated May 26, 2015, by
the Japanese Patent Office as the International Searching Authority
for International Application No. PCT/JP2015/056470. cited by
applicant .
Written Opinion (PCT/ISA/237) dated May 26, 2015, by the Japanese
Patent Office as the International Searching Authority for
International Application No. PCT/JP2015/056470. cited by
applicant.
|
Primary Examiner: Leon, Jr.; Jorge
Attorney, Agent or Firm: Buchanan Ingersoll & Rooney
PC
Claims
The invention claimed is:
1. A system for controlling valve opening/closing timing,
comprising: a valve opening/closing timing control device having: a
drive-side rotary body that rotates synchronously with a crankshaft
of an internal combustion engine; a driven-side rotary body that is
contained within the drive-side rotary body, and rotates in unity
and coaxially with a camshaft for valve opening/closing; and a lock
mechanism that includes a lock member supported slidably in a guide
hole of one of the drive-side rotary body and the driven-side
rotary body, a recess formed in the other of the drive-side rotary
body and the driven-side rotary body, and a biasing member that
biases the lock member, the lock mechanism maintaining the
drive-side rotary body and the driven-side rotary body in a lock
position where the drive-side rotary body and the driven-side
rotary body are held at a predetermined relative rotation phase
position by the lock member engaging in the recess due to biasing
force of the biasing member; and a control unit having: a first
control valve that selectively switches, among an advance chamber
and a retard chamber formed between the drive-side rotary body and
the driven-side rotary body, between an advance position where a
relative rotation phase is displaced in an advance direction by
supply of a fluid to the advance chamber, and a retard position
where the relative rotation phase is displaced in a retard
direction by supply of the fluid to the retard chamber, and a
neutral position where the relative rotation phase is held by
stoppage of supply of the fluid to the advance chamber and the
retard chamber; and a second control valve switchable from the lock
position to an unlock position by the lock member disengaging from
the recess, by fluid pressure acting on the lock member in a
direction against the biasing force of the biasing member; the
control unit executing phase control that changes the relative
rotation phase and unlock control that releases a locked state of
the lock mechanism by controlling at least any one of the first
control valve and the second control valve, wherein the unlock
control is executed such that by the second control valve being set
to the unlock position, and setting the first control valve to any
one of the advance position and the retard position, the lock
member contacts an inner wall of the recess based on displacement
force in a direction against a cam average torque of the camshaft,
and then, by the first control valve being switched to and
maintained at the neutral position, an operation in which the lock
member separates from the inner wall due to the cam average torque
is performed in a predetermined interval.
2. The system for controlling valve opening/closing timing
according to claim 1, wherein the predetermined interval is changed
according to temperature of the fluid.
3. The system for controlling valve opening/closing timing
according to claim 1, wherein the predetermined interval is changed
according to pressure of the fluid.
4. The system for controlling valve opening/closing timing
according to claim 1, comprising a phase sensor that detects the
relative rotation phase, wherein in a case where the phase control
is executed after the unlock control was continued for a set time
period, and even with execution of this phase control, displacement
of the relative rotation phase is not detected by the phase sensor,
the predetermined interval is set to longer than a predetermined
value and then the unlock control is executed again.
Description
TECHNICAL FIELD
The present invention relates to a system for controlling valve
opening/closing timing, and more specifically, relates to an
improvement in technology for reliably unlocking a lock mechanism
of a valve opening/closing timing control device.
BACKGROUND ART
Patent Document 1 describes a control mode in which, when an unlock
request has occurred, a lock member is driven in an unlocking
direction, and while continuing this driving, phase feedback
control is not performed until passage of a predetermined time
period after occurrence of the unlock request, and after the
predetermined time period has passed, control shifts to a feedback
control that maintains a relative rotation phase (a camshaft phase
in Patent Document 1) near an intermediate lock phase.
CITATION LIST
Patent Literature
Patent Document 1: JP 2010-138699A (claim 11, Paragraphs 0018 to
0021, for example).
SUMMARY OF INVENTION
Technical Problem
A lock mechanism of a valve opening/closing timing control device,
as also described in Patent Document 1, is configured with, for
example, a lock member supported so as to be capable of moving to
one of a drive-side rotary body and a driven-side rotary body, a
recess where the lock member is engaged or released in the other of
the drive-side rotary body and the driven-side rotary body, and a
spring causing a biasing force that causes the lock member to
engage in the recess to act.
Also, in the valve opening/closing timing control device, a fluid
path is formed that causes pressure of a fluid to act on a lock
member that is engaged in a recess for locking, thereby causing the
lock member to operate in the unlocking direction, and a control
valve is provided that supplies fluid to or discharges fluid from
this fluid path.
When unlocking the lock mechanism, there are instances where the
relative rotation phase is changed in parallel with an operation to
eject the lock member from the recess. In such a case, there may be
instances where the lock member is strongly pressed against an
inner wall of the recess, and therefore the lock member is unable
to move in the unlocking direction. In order to avoid such a
situation, in Patent Document 1, control to displace the relative
rotation phase is restricted when driving the lock member in the
unlocking direction.
However, in a situation in which the internal combustion engine
operates, a phenomenon occurs in which a cam average torque from a
camshaft acts on the valve opening/closing timing control device,
thus displacing the relative rotation phase in a predetermined
direction, and as a result, the lock member is pushed against the
inner face of the recess.
When the lock member is pressed against the inner face of the
recess in this manner, an operation to eject the lock member from
the recess is difficult even when not performing an operation to
displace the relative rotation phase, so there is room for
improvement.
It is an object of the present invention to rationally configure a
system for controlling valve opening/closing timing that allows an
unlocking operation to be reliably performed.
Solution to Problem
The present invention is characterized by providing:
a valve opening/closing timing control device having: a drive-side
rotary body that rotates synchronously with a crankshaft of an
internal combustion engine; a driven-side rotary body that is
contained within the drive-side rotary body, and rotates in unity
and coaxially with a camshaft for valve opening/closing; and a lock
mechanism that includes a lock member supported slidably in a guide
hole of one of the drive-side rotary body and the driven-side
rotary body, a recess formed in the other of the drive-side rotary
body and the driven-side rotary body, and a biasing member that
biases the lock member, the lock mechanism maintaining the
drive-side rotary body and the driven-side rotary body in a lock
position where the drive-side rotary body and the driven-side
rotary body are held at a predetermined relative rotation phase by
the lock member engaging in the recess due to biasing force of the
biasing member; and
a control unit having: a first control valve that selectively
switches, among an advance chamber and a retard chamber formed
between the drive-side rotary body and the driven-side rotary body,
between an advance position where the relative rotation phase is
displaced in an advance direction by supply of a fluid to the
advance chamber, and a retard position where the relative rotation
phase is displaced in a retard direction by supply of the fluid to
the retard chamber, and a neutral position where the relative
rotation phase is held by stoppage of supply of the fluid to the
advance chamber and the retard chamber; and a second control valve
switchable from the lock position to an unlock position by the lock
member disengaging from the recess, by fluid pressure acting on the
lock member in a direction against the biasing force of the biasing
member; the control unit executing phase control that changes the
relative rotation phase and unlock control that releases a locked
state of the lock mechanism by controlling at least any one of the
first control valve and the second control valve,
in which the unlock control is executed such that by the second
control valve being set to the unlock position, and setting the
first control valve to any one of the advance position and the
retard position, the lock member contacts an inner wall of the
recess based on displacement force in a direction against a cam
average torque of the camshaft, and then, by the first control
valve being switched to the neutral position, an operation in which
the lock member separates from the inner wall due to the cam
average torque is performed in a predetermined interval.
According to this configuration, when releasing a locked state of
the lock mechanism in the unlock control, the control unit sets the
second control valve to the unlock position. In parallel with this
setting, by the control unit setting the first control valve to the
advance position or the retard position, the relative rotation
phase can be displaced in a direction that separates the lock
member from one inner wall of the recess against cam variable
torque that acts from the camshaft, and the lock member caused to
contact another inner wall of the recess. Afterward, by setting the
first control valve to an intermediate position, the relative
rotation phase is displaced in a direction that the lock member
separates from the another inner wall of the recess due to cam
variable torque that acts from the camshaft.
By performing this contact and separation in the set interval, a
state in which the lock member does not contact an inner wall of
the recess is created, and by reducing frictional force that acts
on the lock member from an inner wall of the recess, operation of
the lock member is allowed to be reliably performed.
As a result, a system for controlling valve opening/closing timing
that allows an unlocking operation to be reliably performed is
configured.
In the present invention, the interval may also be changed
according to temperature of the fluid.
When the temperature of the fluid is low and viscosity is high,
even if the fluid is supplied from the first control valve to the
advance chamber or the retard chamber, the time period from the
start of supply until pressure acts in the advance chamber or the
retard chamber and displacement of the relative rotation phase
starts becomes longer. For such reasons, by changing the interval
according to the temperature of the fluid, it is possible to
reliably operate the lock member to a position in contact with
another inner wall of the recess, and afterward, create a state in
which the lock member is caused to separate from that another inner
wall.
In the present invention, the interval may also be changed
according to pressure of the fluid.
When the pressure of the fluid is low, even if the fluid is
supplied from the first control valve to the advance chamber or the
retard chamber, the time period from the start of supply until
pressure acts in the advance chamber or the retard chamber and
displacement of the relative rotation phase starts becomes longer.
For such reasons, by changing the interval according to the
pressure of the fluid, it is possible to reliably operate the lock
member to a position in contact with another inner wall of the
recess, and afterward, create a state in which the recess is caused
to separate from that another inner wall.
In the present invention, a configuration may also be adopted in
which a phase sensor that detects the relative rotation phase is
provided, and in a case where the phase control is executed after
the unlock control was continued for a set time period, and even
with execution of this phase control, displacement of the relative
rotation phase is not detected by the phase sensor, the interval is
set to longer than a predetermined value and then the unlock
control is executed again.
In a case where a locked state is not released by performing unlock
control, displacement of the relative rotation phase is not
detected by the phase sensor even if phase control is executed.
Accordingly, in a case where displacement of the relative rotation
phase is not detected, the interval is set to longer than a
predetermined value and then the unlock control is executed again.
As a result, the lock member is reliably operated to a position in
contact with another inner wall of the recess, and afterward, a
state is created in which the lock member is caused to separate
from that another inner wall, so it becomes possible to improve the
reliability of unlocking.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 shows a configuration of a system for controlling valve
opening/closing timing.
FIG. 2 shows a cross-sectional view taken along line II-II of the
valve opening/closing timing control device in FIG. 1.
FIG. 3 shows a cross-sectional view of the valve opening/closing
timing control device in an unlocked state.
FIG. 4 shows a cross-sectional view of the valve opening/closing
timing control device in a most retarded lock phase.
FIG. 5 shows successive changes in the position of a lock member
and a lock recess.
FIG. 6 shows a flowchart of unlocking/phase control.
FIG. 7 is a timing chart showing the relationship of a lock control
valve, a phase control valve, and an internal rotor.
DESCRIPTION OF EMBODIMENTS
Following is a description of an embodiment of the present
disclosure with reference to drawings.
(Basic Configuration)
As shown in FIG. 1, a system for controlling valve opening/closing
timing is configured having a valve opening/closing timing control
device 10 provided in an intake camshaft 3 of an engine E serving
as an internal combustion engine, a phase control valve 21 (one
example of a first control valve) that controls a relative rotation
phase of the valve opening/closing timing control device 10, a lock
control valve 22 (one example of a second control valve) that
controls a lock mechanism L of the valve opening/closing control
device 10, and also a control unit 40 (ECU).
The engine E is configured as a four-cycle engine provided in a
vehicle such as a passenger vehicle, and the valve opening/closing
timing control device 10 realizes a change in intake timing by
changing the rotation phase of a crankshaft 1 and an intake
camshaft 3 of the engine E. The control unit 40 acquires a rotation
speed of the engine E, or alternatively, acquires information
regarding operation by a driver or the like, and controls the
magnetically controlled phase control valve 21 (one example of a
first control valve) and the magnetically operated lock control
valve 22 (one example of a second control valve).
(Valve Opening/Closing Timing Control Device)
As shown in FIGS. 1 to 4, the valve opening/closing timing control
device 10 is provided with an external rotor 11 serving as a
drive-side rotary body that rotates synchronously with the
crankshaft 1 of the engine E, and an internal rotor 12 serving as a
driven-side rotary body connected with a connecting bolt 13 to the
intake camshaft 3, which opens/closes intake valves 1V of a
combustion chamber of the engine E. The internal rotor 12 is
disposed on the same center axis as a rotational center axis X of
the intake camshaft 3, and by containing the internal rotor 12
within the external rotor 11, the respective rotors are capable of
relative rotation around the rotational center axis X.
The external rotor 11 is fastened by a plurality of fastening bolts
16 in a state held between a front plate 14 and a rear plate 15,
and the internal rotor 12 is disposed between the front plate 14
and the rear plate 15. A timing sprocket 15S is formed around the
outer circumference of the rear plate 15.
In the external rotor 11, a plurality of protruding portions 11T
that protrude to the inside in the radius direction are formed as a
single body with the external rotor 11, and the internal rotor 12
is formed in a cylindrical shape having an outer circumference that
closely contacts a protruding end of the plurality of protruding
portions 11T. Therefore, at an intermediate position of protruding
portions 11T that are adjacent in the rotation direction, a
plurality of fluid pressure chambers C are formed on the outer
circumference side of the internal rotor 12. A plurality of vanes
17 serving as dividing portions are provided at the outer
circumference of the internal rotor 12. By dividing a fluid
pressure chamber C with a vane 17, an advance chamber Ca and a
retard chamber Cb are formed.
The advance chamber Ca is a space that allows the relative rotation
phase to be displaced in an advance direction Sa by supplying a
working oil. Conversely, the retard chamber Cb is a space that
allows the relative rotation phase to be displaced in a retard
direction Sb by supplying the working oil.
A timing chain 8 is wrapped around an output sprocket 7 provided in
the crankshaft 1 of the engine E and the timing sprocket 15S of the
external rotor 11, and thus the external rotor 11 rotates
synchronously with the crankshaft 1. Although not shown in the
drawings, a device having a similar configuration as the valve
opening/closing timing control device 10 is also provided at a
front end of the camshaft on an exhaust side, and torque is
transmitted from the timing chain 8 to this device as well.
As shown in FIG. 2, in the valve opening/closing timing control
device 10, the external rotor 11 rotates in a driving rotation
direction S due to driving force from the crankshaft 1. On the
other hand, a direction that the internal rotor 12 rotates relative
to the external rotor 11 in the same direction as the driving
rotation direction S is called an advance direction Sa, and a
rotation direction opposite to this direction is called a retard
direction Sb.
Also, the relative rotation phase in a state where the vane 17 has
attained the end of operation in the advance direction Sa
(including a phase near the end of operation of the vane 17 in the
advance direction Sa) is called a most advanced phase, and a
relative rotation phase in a state where the vane 17 has attained
the end of operation in the retard direction Sb (including a phase
near the end of operation of the vane 17 in the retard direction
Sb) is called a most retarded phase.
As shown in FIG. 1, a torsion spring 18 is provided across the
internal rotor 12 and the front plate 14, and causes a biasing
force to act until, from a state in which the relative rotation
phase of the external rotor 11 and the internal rotor 12 (referred
to below as the relative rotation phase) is in a most retarded
state, the relative rotation phase attains an intermediate lock
phase P2.
(Valve Opening/Closing Timing Control Mechanism: Lock
Mechanism)
The valve opening/closing timing control device 10 is provided with
a pair of the lock mechanisms L that are capable of holding the
rotation phase at a most retarded lock phase P1 (one example of a
first lock phase) serving as the most retarded phase as shown in
FIG. 4, and the intermediate lock phase P2 (one example of a second
lock phase), which is intermediate between the most advanced phase
and the most retarded phase as shown in FIG. 2.
The respective lock mechanisms L are provided with a pair of lock
members 31 that are supported by the external rotor 11 such that a
protruding end of the lock members 31 is capable of approaching or
separating from the rotational center axis X, and a lock spring 32
(one example of a biasing member) that biases the respective lock
members 31 in the protruding direction. A pair of intermediate lock
recesses 33 where the pair of lock members 31 independently engage
in the intermediate lock phase P2, and a most retarded lock recess
34 where one of the lock members 31 engages when in the most
retarded lock phase P1, are formed in the internal rotor 12.
Also, the lock members 31 are configured with plate-like material,
and in the external rotor 11, are inserted so as to be capable of
sliding movement in guide holes 35 formed in a radial shape
centered on the rotational center axis X. The intermediate lock
recess 33 and the most retarded lock recess 34 are formed in a
groove-like shape having an attitude parallel to the rotational
center axis X.
(Hydraulic Control System)
As shown in FIGS. 1 to 4, in the system for controlling valve
opening/closing timing, in the engine E, a hydraulic pump P is
provided that sucks out oil of an oil pan with driving force of the
engine E, and sends this out as the working oil (one example of a
fluid), and is provided with a fluid path system that supplies the
working oil from the hydraulic pump P to the phase control valve 21
and the lock control valve 22.
Also, an advance fluid path 24 in communication from the phase
control valve 21 to the advance chamber Ca of the internal rotor
12, and a retard fluid path 25 in communication from the phase
control valve 21 to the retard chamber Cb, are formed, and the
advance fluid path 24 is in communication with the most retarded
lock recess 34. Further, an unlock fluid path 26 is formed in
communication from the lock control valve 22 to the intermediate
lock recess 33 of the internal rotor 12.
The phase control valve 21 is configured to be capable of
selectively switching between an advance position, a neutral
position, and a retard position by adjustment of electrical power
supplied to an electromagnetic solenoid of the phase control valve
21. In the advance position, the working oil of the hydraulic pump
P is supplied from the advance fluid path 24 to the advance chamber
Ca, and the working oil is discharged from the retard chamber Cb,
thereby displacing the relative rotation phase in the advance
direction Sa.
Also, in the neutral position, the phase control valve 21 maintains
the relative rotation phase without supplying fluid to or
discharging fluid from the advance fluid path 24 or the retard
fluid path 25. In the retard position, the working oil of the
hydraulic pump P is supplied from the retard fluid path 25 to the
retard chamber Cb, and the working oil is discharged from the
advance chamber Ca, thereby displacing the relative rotation phase
in the retard direction Sb. The neutral position is positioned
between the advance position and the retard position in the movable
range of a spool of the phase control valve 21.
The lock control valve 22 is configured to be capable of operation
to a lock position and an unlock position by adjustment of
electrical power supplied to an electromagnetic solenoid of the
lock control valve 22. In the lock position, the working oil is
discharged from the unlock fluid path 26, enabling a lock member 31
in the unlock position to shift to a locked state, and maintaining
the locked state of a lock member 31 that is already in the lock
position.
On the other hand, in the unlock position, the working oil is
supplied to the unlock fluid path 26, causing a lock member 31 that
is in a state engaged into the intermediate lock recess 33 to
operate to a position (an ejecting position) disengaging from the
intermediate lock recess 33 against the biasing force of the lock
spring 32, thereby releasing the locked state.
(Control Unit/Control Mode)
The control unit 40 is configured as an ECU, where signals are
input from a shaft sensor 1S, a phase sensor 46, a temperature
sensor 47, and a pressure sensor 48. The shaft sensor 1S detects
the rotation speed and the rotation phase of the crankshaft 1. The
phase sensor 46 detects the relative rotation phase. The
temperature sensor 47 detects cooling water temperature (equivalent
to oil temperature of the working oil) of the engine E. The
pressure sensor 48 detects the pressure of the working oil
discharged from the hydraulic pump P.
In the control unit 40, software that executes phase control, lock
shift control, and unlock control is installed. In the phase
control, in a state in which a detection signal from the phase
sensor 46 is fed back to the control unit 40, the lock control
valve 22 is maintained at the unlock position, and by setting the
phase control valve 21 to the advance position or the retard
position, the relative rotation phase is displaced in the direction
of a target relative rotation phase.
In the lock shift control, when holding the relative rotation phase
at the intermediate lock phase P2, the lock control valve 22 is set
to the lock position, and the phase control valve 21 is set to the
advance position or the retard position, thereby displacing the
relative rotation phase in the direction of the intermediate lock
phase P2. When the relative rotation phase detected by the phase
sensor 46 by this displacement has been maintained at the
intermediate lock phase P2, it is decided that a locked state has
been attained.
In an example of the unlock control executed from a state where the
lock mechanism L is in a state locked at the intermediate lock
phase P2, the lock control valve 22 is set to the unlock position,
and after the lock member 31 has been reliably disengaged from the
intermediate lock recess 33, control is performed to shift to the
phase control.
The present disclosure is characterized by control to disengage
(eject) the lock member 31 from the intermediate lock recess 33,
and that control mode is described below.
When the lock mechanism L is in a state locked at the intermediate
lock phase P2, and the working oil is not being supplied to the
advance chamber Ca, as shown in FIG. 5(a), the relative rotation
phase is displaced in the retard direction Sb by a cam average
torque T that acts from the intake camshaft 3. Thus, the phase is
set to an `initial phase` in which, as shown in FIG. 5(a), an end
of the lock member 31 contacts one inner wall (a first wall face
33P) of the intermediate lock recess 33, and an intermediate
portion of the lock member 31 contacts one guide face (a first
guide face 35P) of the guide hole 35.
The flowchart in FIG. 6 shows an overview of `unlock/phase control`
to disengage the lock member 31 in such a contact state from the
intermediate lock recess 33, and displace the relative rotation
phase. In this control, oil temperature information is acquired
from the temperature sensor 47, oil pressure information of the
working oil is acquired from the pressure sensor 48, and based on
these items of information, an initial control time period (TP), a
first setting time period (T1), and a second setting time period
(T2) are set (steps #01 and #02).
The timing chart in FIG. 7 shows the relationship between the
initial control time period (TP), the first setting time period
(T1), and the second setting time period (T2). Also, in the present
disclosure, a value (summed value) obtained by adding the first
setting time period (T1) and the second setting time period (T2) is
an interval used as a period for creating a situation that
facilitates release of the locked state of the lock member 31.
The initial control time period (TP), the first setting time period
(T1), and the second setting time period (T2) are stored in advance
as table data or the like associated with oil temperature
information and oil pressure information, and in step #02, a
processing mode is set such that data stored in advance is read
out. Note that a configuration may also be adopted in which the
initial control time period (TP), the first setting time period
(T1), and the second setting time period (T2) are stored as initial
values of predetermined values, and the processing mode is set so
as to set the respective time periods by performing a calculation
on the initial values, such as multiplying a coefficient based on
the temperature information or the pressure information.
In this control, when the oil temperature of the working oil is low
and viscosity is high, the speed of displacement of the relative
rotation phase in any direction among the advance direction Sa and
the retard direction Sb decreases. Also, when the oil temperature
of the working oil is high and viscosity is low, the speed of
displacement of the relative rotation phase decreases due to
leakage of the working oil. Similarly, when the pressure of the
working oil discharged from the hydraulic pump P is low, the speed
of displacement in a case where the working oil has been supplied
to any of the advance chamber Ca and the retard chamber Cb
decreases. In order to eliminate such problems, the respective time
periods are set in step #02.
Next, by setting the lock control valve 22 to the unlock position,
oil pressure is caused to act in the unlock fluid path 26, and thus
the phase control valve 21 operates to the advance position for the
initial control time period (TP) (steps #03 and #04).
In step #03, first a state is created in which oil pressure is
caused to act continuously on the lock member 31 in the unlocking
direction. In step #04, by operating the phase control valve 21 to
the advance position for the initial control time period (TP), the
relative rotation phase is displaced in the advance direction Sa by
a torque R against the above-described cam average torque T due to
pressure of the working oil that acts in the advance chamber Ca,
and thus the internal rotor 12 is set to a `start phase` shown in
FIG. 5(b).
In the `start phase`, an end of the lock member 31 is separated
from the first wall face 33P by the torque R, and this end is
caused to contact a second wall face 33Q at a position opposing the
first wall face 33P. At the same time, the intermediate portion of
the lock member 31 is separated from the first guide face 35P, and
caused to contact a second guide face 35Q at a position opposing
the first guide face 35P. The initial control time period (TP) is
set so as to attain this sort of position relationship.
Next, the phase control valve 21 is operated to the neutral
position for the first setting time period (T1), and afterward, the
phase control valve 21 is operated to the advance position for the
second setting time period (T2) (steps #05 and #06).
When the phase control valve 21 has been set to the neutral
position by the control in step #05, the working oil is not
supplied to the advance chamber Ca and the retard chamber Cb.
Accordingly, displacement of the relative rotation phase in the
retard direction Sb is started by the phenomenon of the working oil
leaking from the advance chamber Ca, and action of the cam average
torque T that acts from the intake camshaft 3. This displacement is
performed at a low speed, and by this displacement, the lock member
31 attains a `return phase` shown in FIG. 5(d), through the phase
shown in FIG. 5(c).
The first setting time period (T1) is set to a time period shorter
than the time period in which the lock member 31 attains the
`initial phase`, and is set such that after the first setting time
period (T1) has passed, the lock member 31 attains the `return
phase`.
Afterward, by the control in step #06, by setting the phase control
valve 21 to the advance position for the second setting time period
(T2), the second setting time period (T2) is set such that the
internal rotor 12 is returned to the `start phase` shown in FIG.
5(b).
That is, after setting the internal rotor 12 to the `start phase`
shown in FIG. 5(b), in a case where the relative rotation phase is
displaced in the retard direction Sb by leakage of the working oil
and the cam average torque T that acts from the intake camshaft 3,
this displacement is caused to be performed at low speed, so the
phase control valve 21 is set to the neutral position, and not set
to the advance position.
Thus, a state is created in which the lock member 31 separates from
the guide face of the guide hole 35 at the same time as separating
from the wall face of the intermediate lock recess 33, so a
reduction of resistance that acts on the lock member 31 is
realized. Because the resistance that acts on the lock member 31 is
reduced in this way, ejection of the lock member 31 from the
intermediate lock recess 33 by the oil pressure that acts on the
lock member 31 is facilitated.
Also, in this control, the `return phase` is determined by the
first setting time period (T1), but the `return phase` is not a
predetermined phase. Therefore, the interval may also be set such
that the `return phase` shown in FIG. 5(d) matches the `initial
phase` shown in FIG. 5(a).
Also, the control to displace the relative rotation phase from the
`start phase` to the `return phase`, and afterward return to the
`start phase`, is repeatedly performed until a counter value CT,
indicating a number of times of this return, attains a value N that
has been set in advance. After this return has been attained N
times, the relative rotation phase is displaced by setting the
phase control valve 21 to a position (the advance position or the
retard position) corresponding to the target phase (steps #07 to
#09).
Next, when the control in step #09 has been executed, in a case
where displacement of the relative rotation phase in the direction
of the target phase could not be confirmed with detection by the
phase sensor 46, the first setting time period (T1) and the second
setting time period (T2) are extended, and again the control from
step #03 onward is repeatedly executed (steps #10 to #12).
OTHER EMBODIMENTS
Other than the embodiment described above, the present disclosure
may also be configured as follows.
(a) This other embodiment (a) applies to a configuration in which
the valve opening/closing timing control device 10 is provided in
an exhaust camshaft. In a valve opening/closing timing control
device 10 provided in an exhaust camshaft, cam average torque from
the exhaust camshaft acts in the advance direction Sa. Accordingly,
in the `initial phase`, the lock member 31 contacts a wall
face/guide face that is opposite to those shown in FIG. 5(a).
Therefore, the phase control valve 21 is set to the retard position
in order to shift to the `start phase`, but the control mode of the
phase control valve 21 is merely reversed, and the control mode for
releasing the locked state of the lock mechanism L can be performed
in a manner basically the same as described in the above
embodiment.
With the configuration of this other embodiment (a) as well, it is
possible to reliably unlock a lock mechanism L of the valve
opening/closing timing control device 10 provided in an exhaust
camshaft.
(b) A control mode is set such that the first setting time period
(T1) and the second setting time period (T2) are set based on a
rotation speed of the engine E detected by the shaft sensor 1S,
without using detection results of the pressure sensor 48. That is,
as the rotation speed of the engine E increases, the oil pressure
of the working oil discharged from the hydraulic pump P also
increases. Accordingly, by adopting such settings, even without
providing the pressure sensor 48, it is possible to reflect the oil
pressure in the interval, and therefore the configuration also
becomes simpler and less expensive.
(c) As the phase sensor 46, a sensor is used that has properties of
being able to detect displacement of an end of the lock member 31
between the first wall face 33P and the second wall face 33Q of the
intermediate lock recess 33. In this configuration, the phase
control valve 21 is set to the neutral position, a time period
until the phase sensor 46 detects that the lock member 31 has
attained displacement from the `start phase` to the `return phase`
is used as the first setting time period (T1), and a time period
until the phase sensor 46 detects that the lock member 31 has
attained the `start phase` is used as the second setting time
period (T2). In this control, changing the first setting time
period (T1) and the second setting time period (T2) becomes
possible by changing the `return phase`.
Also, in this other embodiment (c), the phase control valve 21 is
set to the advance position after the phase sensor 46 has detected
that the lock member 31 has attained the `return phase`, and by
setting the phase control valve 21 to the advance position,
feedback control to set the phase control valve 21 to the neutral
position becomes possible after the lock member 31 has attained the
`start phase`.
(d) As the configuration of the lock mechanism L, a configuration
may be adopted in which a single lock member 31 is provided, or a
configuration may be adopted in which, for example, the lock member
31 is provided so as to be movable relative to a vane of the
internal rotor 12 in a direction along the rotational center axis
X, and the intermediate lock recess 33 is formed in the rear plate
15.
(e) A configuration may also be adopted in which, for example, in a
case where displacement of the relative rotation phase cannot be
confirmed in step #10 of the above-described flowchart, and so the
initial control time period (TP), the first setting time period
(T1), and the second setting time period (T2) are extended, the
time periods thus extended are set as initial values and stored in
a memory or the like.
By storing initial values that have been extended in this way,
based on information acquired afterward from the temperature sensor
47, the pressure sensor 48, and the like, it is possible to set the
initial control time period (TP), the first setting time period
(T1), and the second setting time period (T2) to appropriate
values.
INDUSTRIAL APPLICABILITY
The present invention is applicable to valve opening/closing timing
control devices provided with a lock mechanism causing a lock
member to be engaged in or released from a lock recess.
REFERENCE SIGNS LIST
1: crankshaft 3: camshaft (intake camshaft) 10: valve
opening/closing timing control device 11: drive-side rotary body
(external rotor) 12: driven-side rotary body (internal rotor) 21:
first control valve (phase control valve) 22: second control valve
(lock control valve) 31: lock member 32: biasing member (lock
spring) 33: recess (intermediate lock recess) 33P: inner wall
(first wall face) 35: guide hole 40: control unit 46: phase sensor
Ca: advance chamber Cb: retard chamber E: internal combustion
engine (engine) L: lock mechanism T: cam average torque
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